The present invention relates to a method of feeding sheet material.
The present invention may be used to advantage for feeding sheets of wrapping material to a folding station of a cellophaning machine for cellophaning packets of cigarettes, to which the following description refers purely by way of example.
On cellophaning machines, the packets for wrapping are fed successively through a folding station along a first path extending in a first direction; corresponding sheets of wrapping material are fed successively to the folding station along a second path extending in a second direction substantially perpendicular to the first direction; and each sheet is arrested at the folding station in such a position as to interfere with the first path and be carried off and folded into a U by the respective packet traveling through the folding station, and so commence the formation of a tubular wrapping about the packet.
On known cellophaning machines of the above type, the sheets of wrapping material are fed through and arrested at the folding station by a pair of suction belts, which extend in the second direction, engage two opposite peripheral longitudinal portions of the sheet, are separated by a distance greater than the width of the packets, and are located on either side of the path along which the packets are fed.
The two suction belts described pose several drawbacks, on account of the normally limited amount of space available, and the complex structure resulting from the pneumatic suction devices of the belts at the folding station.
Moreover, the belts generate concentrated low-pressure regions, which are unsuitable for conveying relatively thin sheet material, particularly material of a few microns in thickness.